Conventionally, a title extraction device is proposed which scans black pixels in a document image; extracts a rectangular area that circumscribes an area in which the black pixels are connected as a character rectangle; integrates a plurality of adjacent character rectangles and extracts a rectangular area that circumscribes the character rectangles as a character string rectangle; calculates points of title likelihood based on attributes of each character string rectangle such as an underline attribute, a frame attribute, and a ruled line attribute, the position of the character string rectangle in the document image, and a mutual positional relationship; and extracts a character string rectangle having the most points as a title rectangle (refer to Japanese Patent Application Laid-open No. H9-134406).
In addition, a document processing device is proposed which includes: storage means for storing construction data representing a construction of a character string having a high possibility or a character string having a low possibility of becoming a title of a document; input means for inputting document data that represents a computerized document; extracting means for analyzing document data that is input to the input means and extracting character string data that represents a character string; construction analyzing means for analyzing each piece of character string data extracted by the extracting means and specifying, for each character string, a construction of the character string that is described in a document corresponding to the document data; and specifying means for specifying, among character string data extracted by the extracting means, character string data representing a title of a document corresponding to the document data based on a specification result by the construction analyzing means and storage contents of the storage means (refer to Japanese Patent Application Laid-open No. 2006-085582).
Furthermore, various methods of generating a name of image data are proposed (refer to Japanese Patent Application Laid-open No. 2008-171380 and Japanese Patent Application Laid-open No. 2008-538148).